Experiencing pain when bending and straightening the knee is a common concern that can significantly impact daily activities and overall quality of life. The knee, as the body’s largest joint, bears considerable stress, making it susceptible to various conditions that manifest as discomfort during movement. Understanding the potential origins of this pain is a step toward effective management and recovery. This article covers common causes, when to seek professional help, diagnostic approaches, and treatment options for knee pain related to bending and straightening.
Common Causes of Knee Pain
Patellofemoral Pain Syndrome (PFPS), often known as “runner’s knee,” is a frequent cause of pain during knee movement. This condition arises from irritation of the cartilage underneath the kneecap (patella), due to overuse, muscle imbalances, or improper knee alignment. The pain often worsens with activities that repeatedly bend the knee, such as running, squatting, or climbing stairs.
Meniscus tears involve damage to the C-shaped cartilage pads that cushion the knee joint. These tears can occur from twisting the knee, especially when bearing weight, or from age-related degeneration. A torn meniscus can cause pain, swelling, and a sensation of clicking, catching, or locking within the knee, making full bending or straightening difficult.
Osteoarthritis (OA) is a degenerative joint disease characterized by the gradual breakdown of cartilage within the knee. This “wear-and-tear” arthritis commonly affects individuals over 50, leading to bones rubbing directly against each other as the protective cartilage diminishes. Symptoms include pain, stiffness, and swelling, often worsening with activity and after periods of rest.
Tendinitis, an inflammation of tendons, frequently affects the knee. Patellar tendinitis, or “jumper’s knee,” involves the tendon connecting the kneecap to the shinbone, causing pain just below the kneecap that intensifies with jumping, running, or squatting. Quadriceps tendinitis, affecting the tendon above the kneecap, also causes pain that worsens with knee movement, and can include stiffness and warmth.
Bursitis, specifically prepatellar bursitis, involves inflammation of the fluid-filled sacs (bursae) around the knee joint. The prepatellar bursa, at the front of the kneecap, can become inflamed due to repetitive kneeling or direct trauma. This causes localized pain, swelling, and tenderness. Ligament injuries, such as those to the anterior cruciate ligament (ACL), can also contribute, especially if they result in instability or swelling that restricts movement.
When to Seek Medical Attention
While minor knee pain can resolve with self-care, certain symptoms indicate a need for medical evaluation. Seek immediate attention if you experience sudden, severe pain, or if you are unable to bear weight on the affected knee. An obvious deformity of the knee joint also warrants urgent care.
Additional red flags include significant swelling, redness, or warmth around the joint, which could suggest inflammation or infection. If you heard an audible pop or snap at the time of injury, especially if followed by pain and swelling, consult a doctor. The knee locking up, clicking loudly, or feeling unstable and giving way also require medical assessment.
If your knee pain does not improve after a few days of rest and self-care, or if it consistently interferes with daily activities, see a healthcare provider. Accompanying fever or general unwellness alongside knee pain could point to a more serious underlying issue.
Diagnostic Approaches
Medical professionals employ a systematic approach to determine the underlying cause of knee pain. The process begins with a thorough medical history, where the doctor asks about the onset, nature, and progression of your pain, and any activities that exacerbate or alleviate it. This is followed by a physical examination, which involves assessing the knee’s range of motion, palpating for tenderness, and performing specific tests to evaluate ligament stability and cartilage integrity.
Imaging studies are crucial for visualizing the internal structures of the knee. X-rays are commonly used to identify bone abnormalities, fractures, or signs of osteoarthritis, such as narrowing of the joint space or bone spurs. Magnetic Resonance Imaging (MRI) provides detailed images of soft tissues, making it invaluable for diagnosing meniscus tears, ligament injuries, and other soft tissue pathologies not visible on X-rays.
In some cases, a Computed Tomography (CT) scan may be used for a more detailed assessment of bone structures. If inflammatory conditions are suspected, blood tests can help identify systemic issues. Joint fluid analysis may be performed if an infection or gout is a concern.
Treatment Options
Once a diagnosis is made, treatment for knee pain progresses from conservative, non-surgical methods to more invasive interventions if necessary. Initial management often involves the RICE protocol: Rest, Ice, Compression, and Elevation. Rest prevents further injury, ice reduces pain and swelling, compression minimizes swelling, and elevating the leg promotes fluid drainage.
Over-the-counter pain relievers, such as nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, are frequently recommended to reduce pain and inflammation. Physical therapy plays a significant role in recovery, focusing on strengthening muscles around the knee, improving flexibility, and correcting gait abnormalities. Therapists may use exercises, manual therapy, and modalities like taping or bracing to support the joint and reduce stress.
For persistent pain, injections into the knee joint may be considered. Corticosteroid injections provide temporary relief by reducing inflammation directly within the joint. Hyaluronic acid injections, also known as viscosupplementation, lubricate the joint and act as a shock absorber, beneficial for osteoarthritis where natural joint fluid may be diminished.
Surgical intervention is typically reserved for cases where conservative treatments have not provided sufficient relief or for specific injuries requiring repair. Arthroscopy, a minimally invasive procedure, involves small incisions through which a camera and surgical instruments are inserted to repair or remove damaged meniscus tissue. For severe joint degeneration, a total knee replacement may be recommended to alleviate pain and restore function.